Use of pecan hulls for treating muds



Patented June '13, 1944 UNITED STATES PATENT OFFICE USE OFPEC AN BULLS FOR TREATING MU S Frank W. Jessen and Jack L'. Battle, Houston, Tex., assignors to Standard oilDevelopment Company, a corporation of Delaware No Drawing; Application January 5, 1943. 7

Serial No. 471,374

2 Claims- ,The present invention is directed to a method for controlling the characteristics of a mud laden drilling fiuid.

In the rotary drilling of wells it is conventional to use a circulating stream of drilling fluid which serves several purposes among which may be men- 1 tioned the lubrication of the drill bit, the supporting of the wall of the bore hole, the plastering orthe wall to prevent filtration of fluids into or out of the bore hole, the conveyance of the cuttings from the drill bit to the surfaceand theing fluid of an active principle derived from pecans. This active principle is found primarily in the fibrous layer immediately inside the shell or the pecan. The entire shell, including the fibrous layer, can be ground up to a fine powder and used or the fibrous layer may be separated .from the hull and used in a ground condition or .an aqueous or caustic extract of the fibrous layer or o! the entire shell may be employed. In any case, the active principle is employed in conJunctiOn with caustic.

The inner fibrous portion of the pecan in which the bulk of the active principle utilized for the purpose of the present invention is concentrated, constitutes between about 10 and 12% by weight of the pecan hull. Separation "of the fibrous material from the hull is bestaccomplished by subjecting the hull to a relatively short grinding operation in an attrition mill followed by a blowing operation in which the less dense fibrous mate-j rial is separated from the ground hull. This lator the hull the latter can be utilized for the production of active carbon or for other known purposes with a result that the 'raw material for the practice of the present invention is obtainable at a very low cost. s

. The ground fibrous material utilized in the present invention ordinarily will have a particle size such that it will pass through a 200 mesh screen. When ground to this size the fibrous material is soluble to a large degree in water, about 85% going into solution. By the addition of alkali to the water the solubility of the fibrous material is increased. a

By comparison with a known treating agent, commonly employed in the regulation of desired viscosity characteristics of drilling mud, caustic and quebracho extract, the treating agent of the present invention displays very desirable treating characteristics. It has been found, for example, that a slightly better treating. eflect can be obtained with a caustic-pecan mixture containing only one part of caustic for every five parts of pecan hull by weight than can be obtained with ter operation is conveniently 'carriedout by dropping the ground hull through -a horizontall or vertically moving stream or air. The proper length or the grinding operation to provide maximum recovery of the fibrous material may be es-. .tablished with reasonable accuracy by preliminary experiment. Ingeneral, a grinding from two to four hours will ordinarily give satisfactory separation of the two-materials. Such grindingfol lowed by a blowing results in a yield of fibrous "material of about 10 to 12% by weight of thetotal hull, the fibrous material, however, having a largevolume due to its low density. Aiter separation or the fibrous material from a caustic-quebracho mixture containing five parts of caustic to five parts 0! quebrachoby weight. This represents a large saving in caustic for a given treating eflect.

To be specific, a treating agent was made by grinding up pecan shell so as to pass 200 mesh and mixing it with caustic and water. The pecan shell constituted 5% by weight of the mixture and the caustic 1% by'weight. Another treating agent was prepared by mixing quebrachti extract, caustic and water with the quebracho constituting 5% by weight of the mixture and the caustic constituting 5% by weight. The two treating agents were applied to a hydrated shale mud weighing 11.4 pounds per gallon and having a viscosity of 40 centipoises. 4% by volume of each treating agent reduced the viscosity of mud to 7.5 centipoises.

' also observed. The mud before treatment lost 18 35% of its water in 30 minutes at pounds per square inch when tested according'to the method described in a paper entitled "Evaluation of filtration properties of drilling muds" by Mil- 'ton Williams and (1E. Cannon publfihed in the t e st as filtration rate to lit while the same amount inthirtyminutes.

oi the pecan-caustic reduced the filtration to 11% The ground pecan fiber showed greater eflectiveness than the ground whole shell'including the'ilber. Pecan fiber ground to pass 200 mesh was employed to make up a treating agent with r caustic and water, the ground iiber constituting 5% by'weight 0f. the mixture and the caustic constituting 1% by weight. 4% by volumeor this treating agent reduced the viscosity of a 10.3

It will be understood that the new treatingv agent can be prepared as a water or caustic expound per gallon hydrated shale mud, having a1 viscosity of 63 centipoises. to, 9 centipoises. The

treatingagentreduced the viscosity of the same mud to 14 centipoisea 1 Increased quantities oi same quantity of the aforesaid caustic-quebracho the pecan fiber-caustic treating agent eflected a further reduction in viscosity, whereas additionalquantities of the caustic and-quebracho treating did not bring about a further reduction in viscosity. Y

This as centipoise mu'dwhen tested for filtration qualities lost about 17% otits water in 30 minutes at 100 pounds per square inch. 4% by volume oi either of the lastv mentioned treating agents reduced this water loss to about Ti /2%;

Thus thefltreating agent derived from the pecan fiber was considerably better than that-derived from the quebracho both for viscosity reduction and for decreasing water loss by filtration since the pecan fiber treating agent'requlred only 1%.

of caustic as compared to 5% required by the quebracho.

tract as well as a suspension. As previously indicated, a large percent of the fiber goes into solution in any case whether in water or-in caustic. When the whole shell is used, however, the percentage 7 which dissolves is considerably :smaller but even in this case an extract of the I Patent is:

l. A'method for improving the characteristics of an aqueous drilling mud which comprises adding thereto the fibrous material found inside the shell-of pecans in combination with caustic alkali.

2. A method for improving the characteristics or an aqueous drilling mud which comprises add- King thereto a powdery substance obtained by grinding the fibrous layer foundinside the shell of pecans until it passes 200 mesh in combination with caustic alkali.

mam: w. JESSEN.

JACK BATTLE. 

